Nail printing apparatus and printing control method

ABSTRACT

A nail printing apparatus to perform printing on a nail includes an imaging device, an illuminating device, a printing section and a movement mechanism. The imaging device photographs a specific finger including the nail to be printed from a plurality of directions different from each other and acquires a plurality of nail images of the nail. The illuminating device is disposed at a certain position relative to the imaging device and illuminates the nail when the imaging device photographs the nail. The printing section performs the printing on the nail. The movement mechanism moves the imaging device, the illuminating device and the printing section together with one another.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2012-195735 filed on Sep. 6, 2012 and No. 2013-150332 filed on Jul. 19, 2013, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a nail printing apparatus.

2. Description of the Related Art

A nail printing apparatus which is a printer to apply colors and/or designs on finger nails of a person has been known and is disclosed in, for example, Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2003-534083.

Such a nail printing apparatus needs to detect the shape of a finger nail to be printed, for example, in order to identify a region to be printed.

Therefore, the nail printing apparatus is provided with an imaging device (camera) to photograph a nail to detect a nail shape, for example, from a photographed nail image.

In such a conventional nail printing apparatus, however, the imaging device is fixed to the upper part of the apparatus, for example, and the position of the imaging device cannot be adjusted. Accordingly, there may be a case where a nail image cannot be acquired from just above a nail depending on the position of the finger nail to be printed.

Further, when a plurality of fingers are inserted in the nail printing apparatus at one time to be printed in series, the finger nails to be printed are disposed over a large area. This requires the imaging device to photograph a large area.

For example, when four fingers (e.g., index, middle, ring and little fingers) of one hand and one finger (e.g., thumb) of the other hand, for example, are inserted in the nail printing apparatus at one time, a wide-type imaging device to acquire an image with an aspect ratio (i.e., screen size) of 16:9 is necessary so as to photograph all the nails including a nail positioned at the edge part. In this case, the imaging device needs to have a wide-angle lens having a horizontal angle of view (i.e., the angle of view from the left end to the right end of a frame) of about 105° and a diagonal angle of view (i.e., the angle of view from one corner to the other corner of a frame) of about 120°.

The use of such a wide-angle lens, however, causes the amount of light at the periphery part of an image to be smaller than that of the center part of the image owing to the cosine fourth law where incident light inclined with respect to the optical axis decreases in amount of light in proportion to the cosine to the power of four of the inclination angle. Therefore, more illuminating devices such as LEDs are necessary as going toward the edge in order to make up for the deficiency in the amount of light. For example, the amount of light in the case where the incidence angle of light at the edge part is 52. 5° is COS (52.5°)⁴=0.13733 . . . , which is about one-seventh of the amount of light at the center part of the image. This means that seven times as many illuminating devices need to be provided at the edge part as at the center part in order to make the amount of light of the both parts the same. As a result, the apparatus increases in weight and cost.

Further, the image of a nail positioned at the edge part inclines as going toward the edge because the image is taken from a diagonal direction. Therefore, photographing with a wide-angle lens produces an image with a large distortion and makes it difficult to detect an accurate nail shape even when correction processing is performed.

In the case where an imaging device and an illuminating device are fixed to the upper part of the nail printing apparatus, print heads which move for printing and a carriage which supports the print heads have to avoid touching the imaging device and the illuminating device. Accordingly, the heights of the imaging device and the illuminating device need to be higher than those of the print heads and the carriage. This means the height of the whole apparatus needs to be relatively high.

Further, the distance between a nail and the imaging device has to be large in order to make a photographable area large. This requires a large height of the whole apparatus, resulting in further increase in size of the whole apparatus.

Providing a plurality of pairs of imaging device and illuminating device might allow large-area photographing. This is impracticable, however, because this not only increases the number of components and apparatus cost but also makes its circuits and software complicated.

BRIEF SUMMARY OF THE INVENTION

The present invention advantageously provides a nail printing apparatus capable of acquiring nail images appropriately regardless of the nail position without a complicated and large structure, which leads to relatively low cost.

According to a first aspect of the present invention, there is provided a nail printing apparatus to perform printing on a nail, the apparatus including: an imaging device which photographs a specific finger including the nail to be printed from a plurality of directions different from each other and acquires a plurality of nail images of the nail; an illuminating device which illuminates the nail when the imaging device photographs the nail, the illuminating device being disposed at a certain position relative to the imaging device; a printing section which performs the printing on the nail; and a movement mechanism which moves the imaging device, the illuminating device and the printing section together with one another.

According to a second aspect of the present invention, there is provided a printing control method of a nail printing apparatus to perform printing on a nail, the apparatus including an imaging device which photographs a finger, an illuminating device which is disposed at a certain position relative to the imaging device and which illuminates the nail of the finger, a printing section which prints an image on the nail, and a movement mechanism which moves the imaging device, the illuminating device and the printing section together with one another, the method including: moving the imaging device and the illuminating device using the movement mechanism to a plurality of positions, wherein a plurality of directions from the plurality of respective positions toward a specific finger including the nail to be printed are different from each other; illuminating the nail using the illuminating device at each of the positions; photographing the specific finger from the plurality of directions using the imaging device to acquire a plurality of nail images of the nail; and printing the image on the nail using the printing section on the basis of the nail images.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, advantages and features of the present invention will become more fully understood from the detailed description given hereinbelow and the appended drawings which are given by way of illustration only, and thus are not intended as a definition of the limits of the present invention, and wherein:

FIG. 1 is a perspective view conceptually showing a nail printing apparatus in a first embodiment, the cover of the nail printing apparatus being open;

FIG. 2 is a perspective view conceptually showing the main body of the nail printing apparatus in the first embodiment;

FIG. 3 is a front view of the main body of the nail printing apparatus in the first embodiment;

FIG. 4 is a cross-sectional view, along the line IV-IV, of the main body shown in FIG. 3 in the first embodiment;

FIG. 5 is a cross-sectional view, along the line V-V, of the main body shown in FIG. 3 in the first embodiment;

FIG. 6 is a cross-sectional view, along the line VI-VI, of the main body shown in FIG. 3 in the first embodiment;

FIG. 7 is a block diagram showing the principal control configuration of the nail printing apparatus in the first embodiment;

FIG. 8 is a view to explain a printing pitch for printing data in the first embodiment;

FIG. 9 is a perspective view conceptually showing the main body of a nail printing apparatus in a second embodiment;

FIG. 10 is a front view of the main body of the nail printing apparatus in the second embodiment;

FIG. 11 is a cross-sectional view, along the line XI-XI, of the main body shown in FIG. 10 in the second embodiment;

FIG. 12 is a top view of a finger accepting section of the nail printing apparatus in the second embodiment;

FIG. 13 shows a sketch of the main body of a nail printing apparatus in a modification; and

FIG. 14 is a view to explain the structure of the main body of the nail printing apparatus shown in FIG. 13 at the time of printing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A nail printing apparatus in accordance with the present invention is described below in detail through the explanations for the embodiments.

The embodiments described below have various features which are technically preferable to carry out the present invention. The scope of the present invention, however, is not limited to the embodiments below and the examples shown in the drawings.

First Embodiment

A nail printing apparatus in a first embodiment of the present invention is described with reference to FIGS. 1 to 8.

FIG. 1 is a perspective view showing the appearance of the nail printing apparatus in the present embodiment.

FIG. 2 is a perspective view showing the interior construction of the nail printing apparatus.

The nail printing apparatus 1 includes a case body 2 and a cover 4 as shown in FIG. 1.

The cover 4 is rotatably connected with the case body 2 with a hinge 3 disposed at the rear end of the upper surface (top board) of the case body 2.

The cover 4 is rotatable about the hinge 3 between the position where the cover 4 overlaps the top board of the case body 2 and the position where the cover 4 stands upright with respect to the top board of the case body 2 (see FIG. 1).

The case body 2 is formed to be substantially oval in a planar view.

At the front side of the case body 2, an open-and-close plate 5 is provided to be able to rise and fall. The open-and-close plate 5 is connected to the case body 2 with a hinge (not shown) disposed at the lower end of the front surface of the case body 2. The open-and-close plate 5 is for opening and closing the front surface of the case body 2.

The shapes and configurations of the case body 2 and the cover 4 are not limited to those exemplified here.

An operation section 22 is disposed on the upper surface (top board) of the case body 2.

The operation section 22 receives various inputs from a user.

The operation section 22 includes operation buttons 221 to receive various inputs, such as an electrical power switch button to power on the nail printing apparatus 1, a stop switch button to stop its operation, a design selection button to select a design image to be printed on a nail T, and a printing start button for starting printing.

A display section 23 is disposed on the upper surface (top board), almost in its center, of the case body 2.

The display section 23 is constituted of a liquid crystal display (LCD), an organic electroluminescence display, or another flat-panel display.

In the present embodiment, the display section 23 displays as appropriate an image acquired by photographing a printing finger U1 (hereinafter referred to as a “finger image”), a nail image included in the finger image (i.e., the image of the contour of a nail T), a design selection screen for selecting a design image to be printed on a nail T, a thumbnail image for confirming a design, an instruction screen to provide various instructions, and the like.

A touch panel may be integrally formed on the surface of the display section 23. In this case, various instructions can also be inputted through a touching operation with a stylus pen (not shown), which is a wand writing tool with a sharp end, and with a finger tip, for example.

The case body 2 contains the main body 10 of the nail printing apparatus 1.

FIG. 3 is a front view of the main body 10 in the present embodiment.

FIG. 4 is a cross-sectional view along the line IV-IV of FIG. 3 viewed from the direction of the arrows.

As shown in FIGS. 2 to 4, the main body 10 substantially has the shape of a box and includes a lower machine casing 11 and an upper machine casing 12. The lower machine casing 11 is disposed at a lower part in the case body 2. The upper machine casing 12 is disposed over the lower machine casing 11 inside the case body 2, so as to be disposed at an upper part in the case body 2.

In the lower machine casing 11 and the upper machine casing 12, a finger fixation section 30, a printing unit 40, a photographing section 50, a printing maintenance section 60, a cartridge fitting section 70 and a control device 80 (see FIG. 7) are disposed.

The lower machine casing 11 is described below.

As shown in FIGS. 3 and 4, the lower machine casing 11 includes a back plate 111, a bottom plate 112, a pair of side plates 113 and 114, a cartridge container 115 and a dividing wall 116.

The lower ends of the side plates 113 and 114 are connected to the both ends of the bottom plate 112, respectively, so that the side plates 113 and 114 are upright with respect to the bottom plate 112.

The back plate 111 is connected to the rear of the bottom plate 112 and the side plates 113 and 114 so as to cover the back of the space enclosed by the bottom plate 112 and the side plates 113 and 114.

The lower part of the back plate 111 is curved forward to form a recess. The space formed at the back of the lower part of the back plate 111 (i.e., the recess) serves as the cartridge container 115 (see FIG. 4).

In the cartridge container 115, the cartridge fitting section 70 is provided where ink cartridges 71 are attached.

The dividing wall 116 is disposed in the lower machine casing 11 so as to vertically partition the space inside the lower machine casing 11 (i.e., the space enclosed by the back plate 111, the bottom plate 112 and the side plates 113 and 114).

The dividing wall 116 lies substantially horizontally so that the left and right ends of the dividing wall 116 are connected to the side plates 113 and 114, respectively, and so that the rear end of the dividing wall 116 is connected to the back plate 111.

The lower machine casing 11 is provided with the finger fixation section 30 so that the casing 11 and the section 30 are unified.

The finger fixation section 30 is described with reference to FIGS. 3 to 6.

FIG. 5 is a cross-sectional view along the line V-V of FIG. 3 viewed from the direction of the arrows.

FIG. 6 is a cross-sectional view along the line VI-VI of FIG. 3 viewed from the direction of the arrows.

The finger fixation section 30 is constituted of a finger accepting section 31 and a finger escape section 32. The finger accepting section 31 is a section to accept a finger U1 whose nail T is to be printed (printing finger, hereinbelow), and the finger escape section 32 is a section where fingers U2 other than the printing finger U1 (non-printing fingers, hereinbelow) are inserted.

The finger accepting section 31 is disposed over the dividing wall 116 and almost at the center of the lower machine casing 11 in its width direction.

The lower space, formed by the dividing wall 116, of the lower machine casing 11 constitutes the finger escape section 32.

The finger accepting section 31 opens toward the front side (near side) of the lower machine casing 11 and is defined by a printing finger placement section 116 a at the bottom which constitutes a part of the dividing wall 116, partitions 31 a and 31 b at the both sides, a nail contact portion 31 c at the back, and a ceiling 31 d at the top.

The ceiling 31 d has a window 31 e through which the nail T of a printing finger U1 inserted in the finger accepting section 31 is exposed.

Front walls 31 f which cover the front side of the lower machine casing 11 stand upright on the upper surface of the dividing wall 116. The front walls 31 f extend rightward and leftward, respectively, on the front side of the lower machine casing 11.

A pair of guide walls 31 g to guide a printing finger U1 into the finger accepting section 31 stands upright on the upper surface of the dividing wall 116. Each of the guide walls 31 g extends from the end (i.e., the end nearer to the center) of the front wall 31 f toward the finger accepting section 31 so that the guide wall 31 g extends obliquely backward.

The dividing wall 116 can be held between a printing finger U1 inserted in the finger accepting section 31 and non-printing fingers U2 inserted in the finger escape section 32 by a user. Thus, a printing finger U1 inserted in the finger accepting section 31 can be stably fixed.

In the present embodiment, the dividing wall 116 is provided with a bulge 116 b bulging downward at the front end portion of the dividing wall 116. The bulge 116 b may form a taper portion whose thickness gradually decreases toward the near side and gradually increases toward the back. Alternatively, the entire thickness of the bulge 116 b may be larger than that of the back part of the dividing wall 116.

Providing the bulge 116 b at the front end portion of the dividing wall 116 in such a way creates an interspace between nails T of non-printing fingers U2 and the dividing wall 116 when the non-printing fingers U2 after printing are inserted in the finger escape section 32. This can prevent the nails T to come into contact with the bottom surface of the dividing wall 116 and thus prevent ink from adhering to the apparatus. Further, this can also prevent nail designs printed on the nails T from touching the bottom surface of the dividing wall 116 and being rubbed or spoiled.

The printing unit 40 includes guide rods 41, a main carriage 42, guide rods 44, a secondary carriage 45, print heads (printing section) 46, a movement mechanism 47 and the ink cartridges 71. These are disposed mainly in the upper machine casing 12.

That is, as shown in FIGS. 3 and 4, the two guide rods 41 are bridged in parallel between two sideboards of the upper machine casing 12. The main carriage 42 is attached to the guide rods 41 in such a way as to slide thereon.

The two guide rods 44 are bridged in parallel between a front wall 42 a and a back wall 42 b of the main carriage 42. The secondary carriage 45 is attached to the guide rods 44 in such a way as to slide thereon. The print heads 46 are mounted on the secondary carriage 45 at the center of the lower surface thereof.

In the present embodiment, the print heads 46 are inkjet print heads which make ink fine droplets, and directly sprays the fine droplets to a surface to be printed.

In the present embodiment, the print heads 46 of the printing unit 40 print an image (e.g., a design image) on the surface of the nail T of a printing finger U1 on the basis of print data.

In the present embodiment, the printing unit 40 has the print heads 46 for the inks of yellow (Y), magenta (M) and cyan (C), for example. Each of the print heads 46 includes a nozzle array having a plurality of nozzles to eject ink of one of the colors.

The print heads 46 included in the printing unit 40 are not limited to those for the three-color inks. The printing unit 40 may further include a print head 46 for another color ink.

The ink cartridges 71 corresponding to ink to be ejected from the respective print heads 46 are fitted in the cartridge fitting section 70 disposed in the cartridge container 115. The ink in the ink cartridges 71 is supplied to the print heads 46 as appropriate through the cartridge fitting section 70 and ink supply tubes (not shown).

The ink cartridges may be mounted on the print heads 46 themselves.

In the present embodiment, the movement mechanism 47 constituted of a main scanning motor 47 a and a sub-scanning motor 47 b, for example, allows the print heads 46 to move in the X and Y directions in FIG. 6. The X direction is the width direction (right-left direction) of the nail printing apparatus 1, and the Y direction is the depth direction (front-back direction) of the nail printing apparatus 1.

Specifically, the main carriage 42 is connected to the main scanning motor 47 a via a power transmitting unit (not shown), and moves in the right-left direction along the guide rods 41 by forward-reversal rotation of the main scanning motor 47 a.

The secondary carriage 45 is connected to the sub-scanning motor 47 b via a power transmitting unit (not shown), and moves in the front-back direction along the guide rods 44 by forward-reversal rotation of the sub-scanning motor 47 b.

The window 31 e of the finger accepting section 31 is disposed within the range of movement of the print heads 46 when viewed from above. Accordingly, the print heads 46 can move to the position to face the nail T of a printing finger U1 which is exposed through the window 31 e, so as to perform printing on the nail T.

In the present embodiment, the photographing section 50, described later, is also movable in association with the movement of the print heads 46. That is, the movement mechanism 47 allows both the print heads 46 and the photographing section 50 to be movable.

The photographing section 50 includes an imaging device 51 and illuminating devices 52.

The photographing section 50 illuminates, with the illuminating devices 52, the nail T of a printing finger U1 inserted in the finger accepting section 31 and exposed through the window 31 e. The photographing section 50 photographs the printing finger U1 using the imaging device 51 to acquire nail images (or finger images including nail images), which are the images of the nail T of the printing finger U1.

In the present embodiment, the imaging device 51 and the illuminating devices 52 are fixed to a position lateral to the carriage (i.e., the main carriage 42 in the present embodiment) supporting the print heads 46.

Specifically, as shown in FIGS. 2 to 4, a substrate 53 is disposed on the upper surface of the main carriage 42 so that one end portion of the substrate 53 protrudes in the lateral direction from the main carriage 42. The imaging device 51 and the illuminating devices 52 constituting the photographing section 50 are disposed on the lower surface of the protruding portion of the substrate 53 above the dividing wall 116.

The size of the substrate 53 and the positions of the imaging device 51 and the illuminating devices 52 on the substrate 53 are not particularly limited.

Preferable positional relation between the imaging device 51 and illuminating devices 52 and the print heads 46 is such that, when the imaging device 51 and illuminating devices 52 are positioned almost just above the nail T of a printing finger U1 inserted in the finger accepting section 31, the print heads 46 are positioned over a head-cleaning cap mechanism 61 and a waste ink section 62 of the printing maintenance section 60 described later (see FIG. 3). Positioning the imaging device 51 and the illuminating devices 52 in such a way is preferable because the print heads 46 can be cleaned or kept moisturized while the nail T of a printing finger U1 is being photographed from just above.

The photographing section 50 is connected to and controlled by a photographing controller 811 of the control device 80 (see FIG. 7), described later.

The image data acquired by the photographing section 50 may be stored in a storage section 82 described later.

The imaging device 51 is a miniature camera provided with a lens and a solid-state image sensing element having about two million pixels or more and including a built-in driver, for example.

The imaging device 51 photographs a nail T from at least two different positions by being moved by the movement mechanism 47 in order to detect the curvature, for example, of the nail T of the printing finger U1.

In the present embodiment, the movement mechanism 47 can move the imaging device 51 to the position above the nail T of a printing finger U1 inserted in the finger accepting section 31 to photograph the nail T. Accordingly, the area covering one nail T is sufficient as the area to be photographed by the imaging device 51 (hereinafter referred to as “photographable area”).

Therefore, the aspect ratio (i.e., screen size) of an image to be acquired by the imaging device (camera) 51 may be 4:3.

The imaging device 51 may be a wide type to acquire an image whose aspect ratio is 16:9. The imaging device (camera) 51 may have a horizontal angle of view of as small as 73. 3° and does not have to include a wide-angle lens in particular.

When the imaging device 51 is positioned just above the nail T of a printing finger U1 inserted in the finger accepting section 31 and exposed through the window 31 e, the photographable area Ar1 of the imaging device 51 is the area enclosed by the solid heavy line in FIG. 6, for example.

When the imaging device 51 is shifted a little laterally from just above the nail T so as to photograph the nail T from diagonally above, the photographable area Ar2 is the area enclosed by the broken heavy line in FIG. 6, for example.

The extent to which the photographing position is shifted laterally from just above the nail T is set as appropriate.

The illuminating devices 52 are illuminators such as white LEDs.

In the present embodiment, two illuminating devices 52 are disposed at the near side and the back side, respectively, of the imaging device 51, with the imaging device 51 disposed between the two illuminating devices 52. The illuminating devices 52 emit light downward to illuminate the area to be photographed below the imaging device 51.

The number and the positions of illuminating devices 52 are not limited to the example shown in the drawings.

A conventional imaging device (camera) 51 has a larger horizontal angle of view, and conventional illuminating devices 52 can emit light having a larger incidence angle. This leads to reduction in amount of light at the edge part of the area to be photographed owing to the cosine fourth law. In such a conventional case, many illuminating devices 52 are necessary to provide sufficient amount of light at the edge part of the area to be photographed.

In contrast, in the present embodiment, the horizontal angle of view of the imaging device (camera) 51 may be as small as an area enough to cover only one nail T, which means that the horizontal angle of view can be smaller compared with a conventional case. Accordingly, the number of illuminating devices 52 can be smaller than that in the conventional case.

Further, the position of a conventional imaging device is fixed and performs photographing from only one position. In such a case, it is necessary to turn on/off illuminating devices 52, disposed at both sides of the imaging device 51, one at a time for photographing to check the change in shading to estimate the curvature of a nail T.

In contrast, in the present embodiment, the movable imaging device 51 enables photographing of a nail T from at least two different positions so that the area enclosed by the solid heavy line and the area enclosed by the broken heavy line in FIG. 6, for example, are both photographable areas. Thus, the values of curvature and vertical position of a nail T, for example, can be obtained on the basis of at least two acquired images.

In this case, taking the image of a nail T from just above it and further taking multiple images of the nail T from multiple different positions diagonally above it enables more accurate recognition of the nail shape and more accurate determination of the nail curvature on the basis of multiple images.

Since the illuminating devices 52 are fixed closely to the imaging device (camera) 51, the direction from the illuminating devices 52 toward a subject nail T substantially coincides with the direction from the imaging device (camera) 51 toward the subject nail T. This prevents photographed images from being dark and always produces bright photographed images.

The printing maintenance section 60 is disposed on the same level as the finger accepting section 31 above the finger escape section 32, with the dividing wall 116 disposed between the printing maintenance section 60 and the finger escape section 32.

The printing maintenance section 60 is disposed within the range of movement of the print heads 46, when viewed from above.

The printing maintenance section 60 is constituted of at least one of the head-cleaning cap mechanism 61 and the waste ink section 62, for example.

The head-cleaning cap mechanism 61 cleans the print heads 46 and puts a cap on the print heads 46 to keep the print heads 46 moist.

The waste ink section 62 catches excess ink discharged from the print heads 46 to keep their nozzles in good condition, for example.

The printing maintenance section 60 may include a head cleaning mechanism and a cap mechanism independent from each other, instead of the head-cleaning cap mechanism 61.

The control device 80 is disposed on the substrate 13 provided on the upper machine casing 12, for example.

FIG. 7 is a block diagram showing the principal control configuration in the present embodiment.

As shown in FIG. 7, the control device 80 is a computer including a control unit 81 constituted of a central processing unit (CPU) and a storage section 82 constituted of a read only memory (ROM) and a random access memory (RAM), for example (the CPU, ROM and RAM are not shown).

The control device 80 may be configured as a microcontroller unit where the CPU, ROM and RAM are mounted on a single chip.

The storage means is not limited to such a storage section 82 including the ROM and RAM provided in the control device 80, but another storage means may be provided.

The ROM of the storage section 82 contains various programs such as a nail information detection program to detect the shape, height and curvature of nail T from nail images; a print data generation program to generate print data; and a printing control process program to perform a printing control process. Each section of the nail printing apparatus 1 is comprehensively controlled through the execution of these programs by the control device 80.

The storage section 82 includes a design image storage area 821 to store the data of original images Gd of nail designs (see FIG. 8).

The number of pieces of data of the original images Gd of nail designs stored in the design image storage area 821 is not particularly limited.

The data of original images Gd of nail designs is not limited to the data contained in the design image storage area 821 of the storage section 82, but may be loaded from an external storage means, such as a memory card, a USB flash drive and various types of hard disks, into the nail printing apparatus 1 for printing.

The storage section 82 includes a nail information storage area 822 where nail information detected by the nail information detecting section 812 is stored. Nail images taken by the photographing section 50 may also be stored in the storage section 82.

The storage section 82 further includes a correction value storage area 823 containing a correction value for curved surface correction for each type of nail T.

In the present embodiment, nails T of printing fingers U1 are categorized into five types of “flat type”, “medium-flat type”, “standard type”, “medium-round type” and “round type”, as described later. The correction value for curved surface correction is prepared for each of the five types.

The control unit 81 includes the photographing controller 811, the nail information detecting section 812, the print data generating section 813, a printing controller 814 and a display controller 815, in terms of its function.

The functions as the photographing controller 811, the nail information detecting section 812, the print data generating section 813, the printing controller 814 and the display controller 815 are carried out through cooperation between the CPU of the control unit 81 and the programs stored in the ROM of the storage section 82.

The CPU constituting the control unit 81 may read, as needed, a program and data contained in the ROM to execute a process. Alternatively the CPU may execute a process after reading the program and data into a cache in the CPU. In this case, the CPU can perform high-speed processing.

The photographing controller 811 controls the imaging device 51 and the illuminating devices 52 so that the imaging device 51 takes a finger image including the nail image of the nail T of a printing finger U1 inserted in the finger accepting section 31.

In the present embodiment, the photographing controller 811 controls the movement mechanism 47 (i.e., the main scanning motor 47 a and sub-scanning motor 47 b) to move the imaging device 51 and the illuminating devices 52 in right-left, front-back, and oblique directions. The photographing controller 811 controls the imaging device 51 to photograph the nail T of a printing finger U1 from at least two different positions (photographing angles) to acquire at least two nail images.

Specifically, the photographing controller 811 controls the movement mechanism 47 to move the imaging device 51 and the illuminating devices 52 to a position just above a nail T so that the imaging device 51 photographs the photographable area Art shown in FIG. 6 from just above the nail T to acquire a first nail image, which is an image taken from just above the nail T. The photographing controller 811 then controls the movement mechanism 47 to move the imaging device 51 and the illuminating devices 52 to a position diagonally above the nail T so that the imaging device 51 photographs the photographable area Ar2 shown in FIG. 6 from diagonally above the nail T to acquire a second nail image, which is an image taken from diagonally above the nail T.

The number of times the imaging device 51 performs photographing is not limited to two. The imaging device 51 may perform photographing three or more times from different positions and angles.

The positions from which the imaging device 51 photographs a nail T preferably include at least a position just above the nail T for detecting the nail shape.

The nail information detecting section 812 detects nail information on the nail T of a printing finger U1 on the basis of nail images acquired by the imaging device 51.

The nail information includes the information on the contour of nail T (i.e., the nail shape), the height of nail T (i.e., the position of the nail T in the vertical direction; hereinafter referred to as “vertical position of the nail T” or merely as “the position of the nail T”), and the curvature of nail T (i.e., the nail curvature).

The nail information detecting section 812 detects at least one of the nail shape, nail height and nail curvature as the nail information.

In the present embodiment the nail information detecting section 812 detects all of the nail shape, nail height and nail curvature on the basis of nail images.

Specifically, the nail information detecting section 812 detects the contour (shape) and position of a nail T from the finger image including the nail image of the nail T of a printing finger U1 acquired by the imaging device 51. Thus, the contour is acquired as the information represented by an X-Y coordinate, for example.

The nail information detecting section 812 may employ any method to detect the contour (shape) of a nail T.

For example, the nail information detecting section 812 may detect the contour (shape) of a nail T on the basis of the difference in color between the nail T and the other finger portion in the finger image including the nail image of the nail T of a printing finger U1 acquired by the imaging device 51.

The method for detecting the contour (shape) of a nail T is not particularly limited to the above-described method.

The nail information detecting section 812 detects the nail height and nail curvature of a nail T on the basis of a plurality of nail images acquired from different positions (photographing angles) by the imaging device 51 for the nail T of a printing finger U1.

The nail height H is the level of the nail T in the vertical direction thereof. Specifically, the nail height H is a dimension Lh (see FIG. 8) from the printing finger placement section 116 a to the upper surface of the nail T, or from the bottom of the print heads 46 to the upper surface of the nail T.

The nail curvature is the curvature of a nail T in the width direction thereof.

The nail height H and the nail curvature can be estimated by comparing a plurality of nail images acquired from a plurality of different positions (photographing angles) and by detecting the differences in nail shape and shading between the nail images. The nail images may include, for example, an image taken from just above the nail T and an image taken from diagonally above the nail T.

The method for detecting the nail height and nail curvature of a nail T is not limited to the above-described method, but the nail information detecting section 812 may employ any method.

The print data generating section 813 generates data (i.e., the print data Gg in FIG. 8) to be printed on the nail T of a printing finger U1 by the print heads 46 on the basis of the nail information detected by the nail information detecting section 812.

Specifically, the print data generating section 813 performs a fitting process such as reduction in size of an original image Gd of nail design on the basis of the nail shape detected by the nail information detecting section 812.

The print data generating section 813 categorizes the nail T as one of several types according to the nail height and nail curvature detected by the nail information detecting section 812.

The print data generating section 813 then performs curved surface correction on the original image Gd of nail design on the basis of a correction value to generate print data Gg. The correction value is prepared for each nail type and stored in the correction value storage area 823.

The curved surface correction corrects data so that the printing pitch for printing by the print heads 46 is finer in the regions corresponding to the both-side edge parts in width of a nail T than in the center part in width of the nail T. In other words, the curved surface correction corrects data so that more pieces of pixel data are allotted to the regions corresponding to the both-side edge parts in width, whose curvature is large, of a nail T than to the region corresponding to the center part in width of the nail T.

In the present embodiment, the nails T are categorized into five types of “flat type”, “medium-flat type”, “standard type”, “medium-round type”, and “round type”. The “flat type” is a nail substantially flat and having a small curvature, the “medium-flat type” is a nail having a curvature a little larger than that of the “flat type”, the “standard type” is a nail having an average curvature, the “medium-round type” is a nail having a curvature a little larger than that of the “standard type”, and the “round type” is a nail having a large curvature.

The types of nail T are not limited to the five types described above. The nails T may be categorized into about three types or into six or more types. The thresholds of nail height and nail curvature for categorizing may be set as appropriate.

The correction value for curved surface correction for each nail type may be set as appropriate so that the printing pitch becomes gradually finer as the position is closer to the edge of a nail T according to its surface curvature. The extent to which the printing pitch of the both-side edge parts of a nail T is made finer than that of the center part is not particularly limited.

For example, when a nail T is categorized as the “flat type” which is relatively close to a flat plate shape, the correction value for curved surface correction is set to be small. The correction value for curved surface correction is set to be larger for a nail T having a larger nail height and nail curvature (e.g., “round type”).

Specifically, when a nail T is categorized as the “standard type”, an average shape, and the printing pitch at the center part in width is 600 dpi, the printing pitch at the right and left farthest edge parts is set to 2400 dpi and the printing pitch at the intermediate parts is set to 1200 dpi.

The printing pitch is set in accordance with the resolution of the print heads 46. When the upper limit of the printing pitch which can be printed by the print heads 46 is 1800 dpi, for example, the printing pitch of the right and left farthest edge parts is set to 1800 dpi:

Making the printing pitch finer for the regions corresponding to the both-side edge parts of nail T achieves a high-definition image regardless of the shape of a nail T to be printed. Specifically, even when the both-side edge parts of a nail T curve in the direction away from the print heads 46, a high-definition image can be obtained which is free from distortion of nail design and which is substantially free from reduction in density at its edge parts.

The printing controller 814 outputs the print data Gg generated by the print data generating section 813 to the print heads 46 and controls the print heads 46 and the movement mechanism 47 to perform printing on a nail T according to the print data Gg. The movement mechanism 47 includes the main scanning motor 47 a and the sub-scanning motor 47 b to move the print heads 46.

The display controller 815 controls the display section 23 to display various types of screens.

In the present embodiment, the display controller 815 controls the display section 23 to display a nail design selection screen, a finger image acquired by photographing a printing finger U1, a nail image included in the finger image, and various types of instruction screens, for example.

Next, the behavior of and how to use the nail printing apparatus 1 in the present embodiment is described.

In performing printing with the nail printing apparatus 1, a user first powers on the apparatus 1 to start the control device 80.

The display controller 815 controls the display section 23 to display the design selection screen.

The user operates an operation button 221 of the operation section 22, for example, and selects a desired nail design among a plurality of nail designs displayed on the design selection screen. This causes the operation section 22 to output a selection instruction signal so that a nail design to be printed on a nail T is selected.

Next, the user inserts a printing finger U1 in the finger accepting section 31 and inserts non-printing fingers U2 in the finger escape section 32 so as to fix the printing finger U1. The user then operates a printing switch.

In FIG. 6, for example, the left ring finger is inserted in the finger accepting section 31 as a printing finger U1, and the other fingers are inserted in the finger escape section 32 as non-printing fingers U2.

Before the start of a printing operation, the photographing controller 811 controls the photographing section 50 so that the imaging device 51 photographs the printing finger U1 while the illuminating devices 52 illuminate the printing finger U1 in response to an instruction input from the printing switch.

Specifically, the photographing controller 811 allows the movement mechanism 47 to move the imaging device 51 and the illuminating devices 52 to perform photographing from two positions, just above the nail T and diagonally above the nail T, to acquire two nail images taken at the different positions. In the present embodiment, the two nail images are a first nail image taken from just above and a second nail image taken from diagonally above.

After the acquisition of the two nail images, the nail information detecting section 812 detects the contour (shape) and position of the nail T on the basis of the first nail image taken from just above. The nail information detecting section 812 also calculates the nail height (i.e., the vertical position of the nail) on the basis of the first and second nail images to detect (calculate) the nail curvature.

After the nail information detecting section 812 detects the shape, height (i.e., vertical position), and curvature of the nail T, the print data generating section 813 performs the fitting process to change the shape of the original image Gd of nail design to fit the nail T on the basis of the nail information.

The print data generating section 813 categorizes the nail T of the printing finger U1 as one of the five types on the basis of the nail information. The print data generating section 813 then reads the correction value associated with the categorized type from the correction value storage area 823 of the storage section 82. The print data generating section 813 then performs the curved surface correction on the original image Gd of nail design using the read correction value (see FIG. 8). Thus, print data Gg is generated.

The printing controller 814 then outputs the generated print data Gg to the print heads 46 so that the print heads 46 perform printing on the nail T on the basis of the print data Gg.

When performing printing on the nails T of a plurality of fingers, a finger whose nail T has been printed is pulled out of the finger accepting section 31 and a finger whose nail T is to be printed next is inserted in the finger accepting section 31 as a printing finger U1. The nail images of the nail T are then acquired, and the above-described processes are repeated.

As described above, the nail printing apparatus 1 in the present embodiment includes the imaging device 51 which photographs the nail T of a printing finger U1 to acquire nail images, the imaging device 51 moved together with the print heads 46 by the movement mechanism 47.

This enables the imaging device 51 to acquire nail images appropriately regardless of the position of a nail T in the finger accepting section 31 without a lot of imaging devices 51 and illuminating devices 52.

This achieves high-precision nail printing without a complicated and large apparatus. That is, high-precision nail printing can be achieved with low cost.

Further, the movement mechanism 47, which is provided to move the print heads 46, is also used to move the imaging device 51 and the illuminating devices 52. This makes efficient use of an existing component, which prevents the apparatus from getting complicated and larger and prevents increase in manufacturing cost.

The photographing section 50 includes the illuminating devices 52 to illuminate the nail T of a printing finger U1 when the imaging device 51 photographs the nail T. The illuminating devices 52, too, are moved together with the imaging device 51 by the movement mechanism 47.

Therefore, a photographable area of the imaging device 51 (i.e., the areas Ar1 and Ar2 in FIG. 6) can be appropriately illuminated regardless of the position and angle from which the imaging device 51 photographs a nail T.

The imaging device 51 is fixed at a position lateral to the carriage (i.e., the main carriage 42 in the present embodiment) supporting the print heads 46. This enables the movement mechanism 47 to move not only the print heads 46 but also the imaging device 51.

Further, the imaging device 51, which is disposed at a position lateral to the main carriage 42, is to be positioned above a nail T to be photographed at some distance from the nail T. Accordingly, sharp images of the nail T can be acquired even with the use of a general camera as the imaging device 51.

Still further, disposing the imaging device 51 and the illuminating devices 52 at a position lateral to the carriage (e.g., the main carriage 42) prevents the carriage from interfering with the devices 51 and 52 when the carriage moves. This enables the apparatus to be shorter in height than a conventional apparatus, leading to reduction in height and size of the whole apparatus.

Since the movement mechanism 47 allows the imaging device 51 to be movable, the imaging device 51 can move surely to a position just above a nail T to take a nail image therefrom without distortion regardless of the position of the nail T in the finger accepting section 31. This allows accurate detection of a nail shape based on the nail image taken from just above.

The movement mechanism 47 enables the imaging device 51 to photograph the nail T of a printing finger U1 from at least two different positions (e.g., positions just above and diagonally above the nail T). That is, the imaging device 51 can acquire a plurality of nail images taken from the different positions and angles. This enables accurate estimation (calculation) of the nail height (i.e., the vertical position of the nail) and the nail curvature by comparing the images and detecting the difference in shape and shading between the images.

The nail printing apparatus 1 in the present embodiment includes the nail information detecting section 812 and the print data generating section 813. The nail information detecting section 812 detects at least one of a nail shape, nail height (i.e., the vertical position of the nail) and nail curvature as nail information on the basis of the nail images acquired by the imaging device 51. (In the present embodiment, the nail information detecting section 812 detects all of the nail shape, nail height and nail curvature.) The print data generating section 813 generates print data to be printed on the nail T of a printing finger U1 by the print heads 46 on the basis of the nail information detected by the nail information detecting section 812.

Thus, print data Gg can be generated from an original image Gd of nail design in accordance with the shape, height, and curvature of a nail T. This achieves high-definition printing having a beautiful finish on any nail T.

Second Embodiment

Next, a nail printing apparatus in a second embodiment of the present invention is described with reference to FIGS. 9 to 12.

The second embodiment is different from the first embodiment only in the structure of a finger fixation section of the nail printing apparatus. Therefore, the following description is focused on the difference between the embodiments.

FIG. 9 is a perspective view conceptually showing the main body of a nail printing apparatus in the second embodiment.

FIG. 10 is a front view of the main body of the nail printing apparatus shown in FIG. 9.

FIG. 11 is a cross-sectional view, along the line XI-XI, shown in FIG. 10 viewed from the direction of the arrows.

As shown in FIGS. 9 to 11, the nail printing apparatus in the second present embodiment is provided with a finger fixation section 90 in a lower machine casing 11 in the same manner as the first embodiment.

In the present embodiment, the finger fixation section 90 is constituted of a finger accepting section 91 where printing fingers U1 are inserted, a finger escape section 92 where non-printing fingers U2 are inserted, and a grip portion 93 to be held tightly between printing fingers U1 inserted in the finger accepting section 91 and non-printing fingers U2 inserted in the finger escape section 92.

The grip portion 93 is constituted of a dividing wall to separate the finger accepting section 91 from the finger escape section 92. The upper surface of the grip portion 93 serves as a flat printing finger placement surface.

The edge part, from which a finger is inserted, of the grip portion 93 preferably has a circular cross section along the finger insertion direction, with the cross section bulging downward from the bottom surface of the grip portion 93, so that the grip portion 93 can be firmly held between printing fingers U1 and non-printing fingers U2 deeply inserted in the finger accepting section 91 and the finger escape section 92, respectively.

The cross-sectional shape of the edge part of the grip portion 93 may be an oval shape or a polygonal shape, instead of a circular shape.

FIG. 12 is a top view of the finger accepting section 91 in the second embodiment.

A plurality of printing fingers U1 can be inserted at a time in the finger accepting section 91 in the present embodiment.

FIG. 12 shows a case where four left fingers except thumb (i.e., index, middle, ring and little fingers) and a right thumb are inserted in the finger accepting section 91 as printing fingers U1.

As shown in FIGS. 9 to 12, the grip portion 93 has a first finger locating portion 93 a at the center part in width thereof. The first finger locating portion 93 a allows the position adjustment of the four fingers (i.e., the index, middle, ring and little fingers) inserted in the finger accepting section 91 in such a way that the portion between the bases of the printing fingers U1 (i.e., the four fingers) and the non-printing finger U2 (i.e., the thumb) inserted in the finger escape section 92 touches the edge part of the first finger locating portion 93 a.

The length of the first finger locating portion 93 a in its width direction X is not particularly limited as long as the grip portion 93 can securely support the four fingers except thumb of one hand.

The grip portion 93 has second finger locating portions 93 b at both sides of the first finger locating portion 93 a. The second finger locating portions 93 b allow the position adjustment of the thumb inserted in the finger accepting section 91 in such a way that the portion between the bases of the printing finger U1 (i.e., the thumb) and the non-printing fingers U2 (i.e., the four fingers) inserted in the finger escape section 92 touches an edge part of the second finger locating portions 93 b.

The edge parts of the second finger locating portions 93 b are positioned posterior to that of the first finger locating portion 93 a in the finger insertion direction Y.

Although the extent to which the position of the edge parts of the second finger locating portions 93 b is different from that of the first finger locating portion 93 a in the finger insertion direction Y is not particularly limited, the extent is preferably determined so that the nails T of the thumb and the other four fingers substantially align in the lateral direction.

A thumb of a human hand is shorter than the other four fingers and the difference in length between the thumb and the other four fingers is 40-75 mm, although there are differences between individuals and depending on how to hold the grip portion. Considering such a difference in length of the thumb and the other fingers, the edge parts of the second finger locating portions 93 b are preferably positioned about 40-75 mm posterior to that of the first finger locating portion 93 a in the finger insertion direction Y.

When using a conventional grip portion where the edge part of a portion to locate four fingers and the edge part of another portion to locate a thumb align, the nails T of the thumb and the other four fingers are quite different in position in the finger insertion direction Y.

In such a conventional case, it is necessary to expand a photographable area which can be photographed by a photographing section 50 and expand a printable area which can be printed by a printing unit 40, described later, so that each area covers all of the nails T of the thumb and the other four fingers.

In contrast, in the present embodiment, since the edge parts of the second finger locating portions 93 b for positional adjustment of thumb lie about 45 mm posterior to the edge part of the first finger locating portion 93 a in the finger insertion direction Y, the nails T of thumb and other four fingers substantially align. This allows the photographable area of the photographing section 50 and the printable area of the printing unit 40 to be smaller than a conventional grip portion.

As shown in FIGS. 9 to 11, the nail printing apparatus of the present embodiment includes a photographing section 50 fixed at a position lateral to the carriage (i.e., a main carriage 42 in the present embodiment) supporting the print heads 46 as in the first embodiment.

A movement mechanism 47 (i.e., a main scanning motor 47 a and a sub-scanning motor 47 b) allows an imaging device (camera) 51 and illuminating devices 52 of the photographing section 50 to move in front, back, right and left directions so that all the nails T of printing fingers U1 inserted in the finger accepting section 91 can be photographed from just above and diagonally above therefrom.

When photographing the left ring finger nail T inserted in the finger accepting section 91 as shown in FIG. 12, for example, the movement mechanism 47 first allows the imaging device 51 and the illuminating devices 52 to move to a position just above the ring finger nail T.

The area enclosed by the solid heavy line in FIG. 12 is the photographable area Ar1 of the imaging device 51.

After that, when photographing the ring finger nail T from diagonally left above (i.e., left in FIG. 12 or the side nearer to the little finger), the movement mechanism 47 allows the imaging device 51 and the illuminating devices 52 to move a little leftward. In this case, the area enclosed by the broken line in FIG. 12 is the photographable area Ar2 of the imaging device 51.

When photographing the ring finger nail T from diagonally right above (i.e., right in FIG. 12 or the side nearer to the index finger), the movement mechanism 47 allows the imaging device 51 and the illuminating devices 52 to move a little rightward. In this case, the area enclosed by the dashed-dotted line in FIG. 12 is the photographable area Ar3 of the imaging device 51.

The number of times the imaging device 51 performs photographing is not limited to three. The imaging device 51 may perform photographing twice, i.e., from just above the nail T and from diagonally left above or diagonally right above the nail T, as in the first embodiment. Alternatively, the imaging device 51 may perform photographing four or more times from different positions and angles.

The positions from which the imaging device 51 photographs a nail T preferably include at least a position just above the nail T for detecting the nail shape.

Since the other structures are the same as those of the first embodiment, the same numbers or alphabets are assigned to the same components between the first and second embodiments and repetitive explanations are omitted.

Next, the behavior of and how to use the nail printing apparatus 1 in the present embodiment is described.

A user first powers on the nail printing apparatus 1 to start a control device 80 and selects a nail design to be printed on a nail T, as in the first embodiment.

Next, the user inserts a plurality of printing fingers U1 in the finger accepting section 91 and inserts non-printing fingers U2 in the finger escape section 92 so as to fix the printing fingers U1. The user then operates a printing switch.

In FIG. 12, for example, the left four fingers other than thumb (i.e., index, middle, ring and little fingers) and the right thumb are inserted in the finger accepting section 91 as printing fingers U1, and the other fingers are inserted in the finger escape section 92 as non-printing fingers U2.

Before the start of a printing operation, a photographing controller 811 controls the photographing section 50 so that the imaging device 51 photographs the printing fingers U1 one by one while the illuminating devices 52 illuminate the printing fingers U1 in response to an instruction input from the printing switch.

When photographing the left ring finger nail T, for example, the photographing controller 811 allows the movement mechanism 47 to move the imaging device 51 and the illuminating devices 52 to perform photographing from three positions, just above, diagonally left above and diagonally right above the ring finger nail T (i.e., the positions from which the areas Ar1-Ar3 in FIG. 12 are to be photographed, respectively). Thus, three nail images taken from different positions are acquired. Specifically, in the present embodiment, a first nail image taken from just above, a second nail image taken from diagonally left above, and a third nail image taken from diagonally right above are acquired.

After the acquisition of the three nail images, a nail information detecting section 812 detects the contour (shape) and position of the nail T on the basis of the first nail image taken from just above. The nail information detecting section 812 also estimates (calculates) the nail height (i.e., the vertical position of the nail) and the nail curvature on the basis of the first to third nail images.

After the nail information detecting section 812 detects the nail shape, nail height (i.e., vertical position of the nail), and nail curvature, a print data generating section 813 performs the fitting process to change the shape of the original image Gd of nail design to fit the nail T on the basis of the nail information. The print data generating section 813 then performs curved surface correction on the original image Gd of nail design as appropriate, and thus, print data Gg is generated.

The printing controller 814 then outputs the generated print data Gg to the print heads 46 so that the print heads 46 perform printing on the nail T on the basis of the print data Gg.

The photographing and printing of a plurality of nails T of printing fingers U1 inserted in the finger accepting section 91 may be performed in such a way that all the nails T are photographed to generate print data Gg for each nail T, and after that, printing is performed on the nails T in series. Alternatively, photographing and printing may be performed individually for each nail T. Specifically, one nail T is photographed, the print data Gg for the nail T is generated, and then printing is performed on the nail T; and after the printing for the nail T, the same processes are repeated for the next nail T, and in the same manner, the same processes are repeated individually for each nail T.

Since the other structures are the same as those of the first embodiment, repetitive explanations are omitted.

As described above, the nail printing apparatus 1 in the second embodiment brings about not only the advantageous effects obtained in the first embodiment but also the following effects.

In the present embodiment, a plurality of fingers, such as the four fingers (e.g., index, middle, ring and little fingers) of one hand and one finger (e.g., thumb) of the other hand, can be inserted in the finger accepting section 91 at a time to be printed in series.

This eliminates the need for a user to insert and pull out fingers each time printing for one nail T is finished, which achieves easy and quick printing of nail design for each finger of one hand or both hands.

Further, since the imaging device 51 moves together with the print heads 46, even a nail T of printing finger U1 positioned at the edge part of the finger accepting section 91 can be photographed from just above. This enables accurate detection of a nail shape on the basis of high-definition images free from distortion for all the nails T.

Further, since the imaging device 51 is moved by the movement mechanism 47, a plurality of nail images taken from different multiple positions and angles, such as the positions just above and diagonally above a nail T, can be acquired regardless of the position of the nail T in the finger accepting section 91.

Accordingly, the nail height (i.e., the vertical position of the nail) and the nail curvature can be estimated (calculated) accurately by comparing these images and detecting the differences in shape and shading between the images for each of the nails T of printing fingers U1 inserted in the finger accepting section 91.

Further, an original image Gd of nail design is changed in shaped to fit to a nail T of a user on the basis of the nail shape, nail height and nail curvature detected with high precision, and a curved surface correction is performed on image data. Therefore, print data to nails T in various shapes can be generated. This achieves high-definition printing having a beautiful finish.

Further, even when a plurality of nails T of printing fingers U1 are disposed over a wide area in the finger accepting section 91, a photographable area may constantly be as small as an area covering only one nail T because the imaging device 51 and the illuminating devices 52 move to the position suitable to photograph each nail T.

This eliminates the need for a wide-angle lens for photographing and prevents the problems of image distortion and reduction in amount of light at the edge part. Therefore, it is sufficient to provide a single set of small-sized imaging device 51 and illuminating devices 52 meant for ordinary photographing. This prevents the apparatus from becoming large and complicated and prevents increase in cost.

It should be understood that the present invention is not limited to the above-described embodiments but may be modified in various manners without departing from the spirit of the invention.

For example, although the imaging device 51 and the illuminating devices 52 of the above-described embodiments are disposed on the lower surface of the protruding portion of the substrate 53 which is disposed on the upper surface of the main carriage 42 in the printing unit 40, the position of the imaging device 51 and the illuminating devices 52 is not particularly limited as long as the imaging device 51 can be moved together with the print heads 46 by the movement mechanism 47. The imaging device 51 and the illuminating devices 52 may be fixed to the secondary carriage 45 or may be directly fixed to the print heads 46, for example.

The imaging device 51 and the illuminating devices 52 of the above-described embodiments are fixed at a position lateral to the carriage (i.e., the main carriage 42 in the present embodiment) supporting the print heads 46. The position of the imaging device 51 and the illuminating devices 52, however, is not limited to a position lateral to the print heads 46 or the carriage, such as the main carriage 42 or the secondary carriage 45, which supports the print heads 46. Alternatively, the devices 51 and 52 may be disposed at the near side or back side of the print heads 46 or the carriage.

Although the imaging device 51 and the illuminating devices 52 of the above-described embodiments are moved together with the print heads 46 by the movement mechanism 47, the mechanism to move the devices 51 and 52 is not limited thereto.

For example, another movement mechanism to move the imaging device 51 and the illuminating devices 52 may be provided separately from the movement mechanism 47 to move the print heads 46.

In the first embodiment, the imaging device 51 is moved by the movement mechanism 47 to photograph the nail T of a printing finger U1 from two different positions and acquires nail information on the basis of the two images acquired in the two time photographing.

Further, in the second embodiment, the imaging device 51 acquires nail information on the basis of three images acquired in three time photographing.

The number of times the imaging device 51 photographs a nail T to acquire nail information (i.e., the shape, height and curvature of nail T), however, is not limited thereto as long as the photographing is performed at least twice. That is, the photographing may be performed four times or more.

For the photographing performed four times or more, for example, a nail T is photographed from a position just above the nail T, and from a plurality of positions with different shift amounts from the just-above position.

In the above-described embodiments, the print data generating section 813 performs the curved surface correction for an original image Gd of nail design to generate print data Gg. Generation of print data Gg by the print data generating section 813, however, is not essential for the present invention.

Alternatively, the data of an original image Gd of nail design may be converted as appropriate using a lookup table (LUT) in the printing controller 814 without separate generation of print data Gg. In this case, the converted data is output to the print heads 46 and printing is controlled to be suitable for the nail shape, for example.

The photographing may be performed the moment the imaging device 51 reaches a position just above a nail T and reaches the position shifted from the just-above position by a predetermined amount while the imaging device 51 is moved by the movement mechanism 47. Alternatively, the imaging device 51 may be stopped at a position just above a nail T and at the position shifted from the just-above position by a predetermined amount to photograph the nail in a stopped state.

Further, images taken by the imaging device 51 are not limited to still images but may be moving images. In this case, the imaging device 51 shoots a moving image while the movement mechanism 47 moves the imaging device 51, and images taken from just above and diagonally above a nail T are captured from the moving image to be used to detect nail information.

Although the print heads 46 in the above-described embodiments are inkjet print heads, the type of the print heads 46 is not limited thereto. For example, a printing tool such as a ballpoint-pen tool and a felt-tip-pen tool may be used to directly touch a nail T to draw a design thereon.

An example of the main body 10 b of such a nail printing apparatus is shown in FIG. 13.

As shown in FIG. 13, a printing unit 40 b includes print heads 46 b including a plurality of drawing pens 48 as printing tools and a movement mechanism 47 to move the print heads 46 b in X and Y directions.

The print heads 46 b are attached to a carriage 43. FIG. 13 shows a case where four print heads 46 b each holding a pen 48 are attached to the carriage 43.

The number of print heads 46 b attached to the carriage 43 is not limited to four, but may be one or may be five or more.

In the present embodiment, the carriage 43, the print heads 46 b, and the pens 48 held by the print heads 46 b constitute a printing section 402 to perform printing on a nail T.

As shown in FIG. 14, the pens 48 held by the print heads 46 b each have a pen shaft 481 and a pen tip 482.

The interior of each pen shaft 481 serves as an ink container.

Various types of ink may be used as the ink contained in each pen shaft 481. The viscosity and particle diameter (i.e., particle size) of coloring material are not particularly limited. For example, ink containing gold and silver glitter, white ink, UV-curable ink, material for gel nails, undercoats, topcoats, and nail polish may be used.

Examples of the types of pen tips 482 include a ballpoint-pen type which allows the ink in the pen shaft 481 to come out through the pen tip 482 pressed against the surface of a nail T for printing, a fiber-pen type which allows the ink to ooze through the felt pen tip for printing, and a brush-pencil type which has a bundle of hair and performs printing with the hair soaked with the ink. The pen tips 482 may have various thicknesses.

The print heads 46 b may have a plurality of pens 48 having colors different from one another. Alternatively, the pens 48 may contain the same-color ink and may have pen tips 482 different from one another only in shape and thickness, for example.

The pens 48 are preferably replaceable by a user.

As shown in FIG. 14, the heights of pens 48 are adjusted so that the pen tips 482 touch a nail T when printing is performed. The movement mechanism 47 moves the print heads 46 b on the basis of print data, and thus, the pens 48 are moved to draw an image on the nail T.

When a photographing section 50 is photographing a nail T, the pens 48 are kept at such a position that the pen tips 482 do not touch the nail T.

The nail printing apparatus equipped with such print heads 46 b also includes the photographing section 50 which includes an imaging device 51 and illuminating devices 52 and fixed at a position lateral to the carriage 43 as in the above-described embodiments.

Such a nail printing apparatus brings about the same effects as the above-described embodiments because the photographing section 50 is moved in front, back, right and left directions by the movement mechanism 47 as in the above-described embodiments.

The scope of the present invention is not limited to the above-described embodiments, but covers the scope of the claims and its equivalents. 

What is claimed is:
 1. A nail printing apparatus to perform printing on a nail, the apparatus comprising: an imaging device which photographs a specific finger including the nail to be printed from a plurality of directions different from each other and acquires a plurality of nail images of the nail; an illuminating device which illuminates the nail when the imaging device photographs the nail, the illuminating device being disposed at a certain position relative to the imaging device; a printing section which performs the printing on the nail; and a movement mechanism which moves the imaging device, the illuminating device and the printing section together with one another.
 2. The nail printing apparatus according to claim 1, wherein the plurality of directions include a first direction from just above the nail toward the nail and a second direction shifting from the first direction to one side of the nail in a width direction of the nail.
 3. The nail printing apparatus according to claim 2, wherein the movement mechanism moves the imaging device to a first position and a second position when the imaging device acquires the nail images, wherein a direction from the first position toward the nail is the first direction, and a direction from the second position toward the nail is the second direction.
 4. The nail printing apparatus according to claim 3, further comprising a printing maintenance section which maintains a print head, the print head being included in the printing section to apply ink to the nail, wherein the imaging device and the printing section are disposed so that the print head is over the printing maintenance section when the imaging device is in the first position.
 5. The nail printing apparatus according to claim 4, wherein the printing section includes a carriage supporting the print head; and wherein the imaging device is fixed to a position lateral to the carriage.
 6. The nail printing apparatus according to claim 1, wherein the illuminating device includes only one pair of light sources arranged in a longitudinal direction of the nail, with the imaging device disposed between the pair of light sources; and wherein the light sources are turned on when the imaging device photographs the nail.
 7. The nail printing apparatus according to claim 1, further comprising: a nail information detecting section which detects a contour of the nail and at least one of a height and a curvature of the nail as nail information on the basis of the nail images acquired by the imaging device; and a print data generating section which corrects image data on the basis of the nail information to generate print data, wherein the printing section is moved by the movement mechanism in accordance with the print data to print an image on the nail.
 8. The nail printing apparatus according to claim 1, wherein the printing section includes a print head which applies ink to the nail; wherein the print head includes at least one printing tool which applies the ink to the nail when a tip of the printing tool touches the nail; and wherein the print head allows the tip of the printing tool to touch the nail when the printing is performed on the nail, and the print head keeps the printing tool at such a position that the tip does not touch the nail when the imaging device is moved by the movement mechanism and acquires the nail images.
 9. A printing control method of a nail printing apparatus to perform printing on a nail, the apparatus including an imaging device which photographs a finger, an illuminating device which is disposed at a certain position relative to the imaging device and which illuminates the nail of the finger, a printing section which prints an image on the nail, and a movement mechanism which moves the imaging device, the illuminating device and the printing section together with one another, the method comprising: moving the imaging device and the illuminating device using the movement mechanism to a plurality of positions, wherein a plurality of directions from the plurality of respective positions toward a specific finger including the nail to be printed are different from each other; illuminating the nail using the illuminating device at each of the positions; photographing the specific finger from the plurality of directions using the imaging device to acquire a plurality of nail images of the nail; and printing the image on the nail using the printing section on the basis of the nail images.
 10. The printing control method according to claim 9, wherein the plurality of directions include a first direction from just above the nail toward the nail and a second direction shifting from the first direction to one side of the nail in a width direction of the nail; and wherein the movement mechanism moves the imaging device to a first position and a second position when the imaging device acquires the nail images, wherein a direction from the first position toward the nail is the first direction, and a direction from the second position toward the nail is the second direction.
 11. The printing control method according to claim 10, wherein the printing section includes a print head which applies ink to the nail; wherein the nail printing apparatus further comprises a printing maintenance section which maintains the print head; wherein the imaging device and the printing section are disposed so that the print head is over the printing maintenance section when the imaging device is in the first position; and wherein the printing maintenance section maintains the print head when the imaging device is moved to the first position by the movement mechanism.
 12. The printing control method according to claim 9, further comprising: acquiring a contour of the nail and at least one of a height and a curvature of the nail as nail information on the basis of the nail images acquired by the imaging device; and correcting image data on the basis of the nail information to generate print data. 